Vol 18, No 1 (2014) > Marine Engineering >

Performance Evaluation of an Optimized Floating Breakwater in Oblique Waves with a Higher-Order Boundary Element Method

Faisal Mahmuddin 1 , Masashi Kashiwagi 2


  1. Department of Naval Architecture, Faculty of Engineering, Universitas Hasanuddin, Makassar 90245, Indonesia
  2. Naval Architecture and Ocean Engineering Department, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan


Abstract: In the previous study, the optimal performance of a two-dimensional (2D) floating breakwater shape was obtained. The performance of this shape was also confirmed with a model experiment in a towing tank. Moreover, the shape’s performance in three dimensions (3D) was investigated in a subsequent study. However, to predict the shape’s performance in a real application more accurately, the shape’s characteristics in oblique waves must also be evaluated. In this study, the performance and characteristics of the model (hydrodynamic forces, body motions, wave elevations, and drift forces) are computed using a higher-orderboundary element method (HOBEM). The HOBEM, which is based on the potential flow theory and uses quadratic representation for quadrilateral panels and velocity potentials, can be used to obtain more accurate results with fewer panels compared to the conventional panel method (CPM). The computational accuracy is confirmed by using Haskind-Newman and energy conservation relations. In thisstudy, 3D wave effects were verified, and the body motions were much smaller compared to the 2D case. In addition, although the performance in terms of wave elevations depends on the measurement positions, the optimal performance obtained in the 2D case can be realized for a longer body length. 
Keywords: 3D wave effects, floating breakwater, higher order boundary element method (HOBEM), oblique waves, performance evaluation
Published at: Vol 18, No 1 (2014) pages: 41-50

Access Counter: 1029 views, 1004 PDF downloads, .

Full PDF Download


J.S. Mani, J. Waterway, Port, Coastal Ocean Eng. 117/2 (1991) 105.

M.R. Gesraha, Appl. Ocean Res. 28/5 (2006) 327.

H.Y. Wang, Z.C. Sun, Ocean Eng. 37/5 (2010) 520.

S.A. Sannasiraj, V. Sundar, R. Sundaravadivelu. Ocean Eng. 25/1 (1998) 27.

A.N. Williams, H.S. Lee, Z. Huang, Ocean Eng. 27/3 (2000) 221.

K. Murali, K.S. Mani, J. Waterway, Port, Coastal Ocean Eng. 123/4 (1997) 172.

M. Kashiwagi, H. Yamada, M. Yasunaga, T. Tsuji, Int. J. Offshore Polar Eng. 17/1 (2007) 39.

M.A. Rahman, N. Mizutani, K. Kawasaki, Coastal Eng. 53/10 (2006) 799.

S. Koshizuka, A. Nobe, Y. Oka, Int. J. Numerical Methods in Fluids. 26 (1998) 751.

W. Koo, Ocean Eng. 36/9 (2009) 723.

F. Mahmuddin, M. Kashiwagi, Proc. of 22nd Int. Society of Offshore and Polar Engineers, Rhodes Island, Greece, 2012, p.1263.

M. Kashiwagi, F. Mahmuddin, Proc. of 22nd Int. Society of Offshore and Polar Engineers, Rhodes Island, Greece, 2012, p.1271.

R.A. Dalrymple, M.A. Losada, P.A. Martin, J. Fluid Mech. 224 (1991) 625.

I.H. Cho, S.T. Kee, M.H. Kim, Appl. Ocean Res. 19/3 (1997) 171.

J. Wu, P.L.F. Liu, Appl. Ocean Res. 10/2 (1998) 66.

Y.H. Zheng, Y.M. Shen, Y.G. You, B.J. Wu, D.S. Jie, Ocean Eng. 33/1 (2006) 59.

M. Kashiwagi, Bulletin Research Institute for Applied Mechanics, Kyushu University Japan, 1995, p.83.

M. Kashiwagi, 3D Boundary Element Method, Seizando Shoten, Co. Ltd., 2003.

T. Haraguchi, S. Ohmatsu, Trans. West-Japan Soc. Naval Architect. 66 (1983) 9.

H. Maruo, J. Ship Res. 4/3 (1960) 1.

J. Newman, J. Ship Res. 1/1 (1967) 51.